/Engine/Plugins/Runtime/RigVM/Source/RigVMDeveloper/Public/RigVMModel/RigVMController.h
The Modified event used to subscribe to changes happening within the Graph. This is broadcasted to for any change happening - not only the changes performed by this Controller - so it can be used for UI Views to react accordingly.
[FRigVMGraphModifiedEvent](API\Plugins\RigVMDeveloper\RigVMModel\FRigVMGraphModifiedEvent) & OnModified()